Standard visual displays take on a variety of forms. Static displays showing a drawn or photographed image have long been used to convey a message or promote an idea. Additionally, in the field of advertisements, traditional posters with an image and some text are often used. These are frequently used outdoors and in areas of high traffic, so as to get the subject matter of the poster greater exposure. More recently, alterable displays have allowed for the use of lighting in conjunction with the static display to enhance or otherwise alter the display.
Yet other advertisements may be made using flat panel display technologies. These displays are readily changeable and editable and can be made to display any of a variety of images or text. These displays are, however, often very expensive, thus making them impractical for many uses. For example, it would not be desirable to place or mount a flat panel display in an area where it could be easily damaged or removed by an unauthorized person.
Still other displays use light guides to illuminate all or part of the display. A light guide can be a hollow box-shaped structure defining an optical cavity or a solid light-guiding plate. The guide can have a surface that is illuminated by light directed into the guide in a direction generally parallel to that surface. The light may be supplied from one or more light sources arranged on an edge of the light guide. Traditional light guides, however, are often expensive and may not allow for the positioning of the display to be altered or have proper or desired distribution of the light throughout the light guide. Moreover they do not allow for the variation of an image or the display of images on different layers.